The present invention relates to biocidic materials and to fiber-plastic composite materials and more particularly, to the production of an antimicrobial biocidic fiber-plastic composite.
Plastic composites, such as fiber-plastic composites, have become increasingly popular because of their variety of applications. In particular, plastic composites made from recycled materials have become popular as a result of environmental concerns.
A plastic composite capable of killing bacteria on contact is also desirable to eliminate health concerns. In some applications, such as food applications, contamination by microorganisms must be avoided. Microbial contamination-of food during packaging and transportation is a serious concern among health professionals. If contamination by the packaging or transportation agents occurs, the effort spent to eliminate pathogenic organisms during processing is wasted. Annually, there are literally thousands of reports of food poisoning that are directly the result of the transportation of the food. Ingestion of these contaminants may cause considerable illness, and in some cases death to the infected person.
Existing plastic treatments to address this problem include bacterial resistant polymers in which the bacteria will not penetrate the polymer itself. This treatment does not use a biocidal that kills bacteria on contact and does not avoid the possibility of contamination through transfer of the organism. Prior attempts to use biocidals within polymers have involved treating plastics with chemicals which have been shown to be harmful to humans.
Accordingly, there is a need for a plastic composite that is capable of killing bacteria on contact without being harmful to humans.
One aspect of the present invention is a method of producing a biocidic fiber-plastic composition. The method comprises obtaining a cellulose fiber material. At least one biocide is mixed with the fiber material such that the biocide binds with the fiber material to form a biocide fiber substrate. A plastic material is mixed with the biocide fiber substrate to form the biocidic fiber-plastic composition.
This method of producing the biocidic fiber-plastic composition preferably includes the additional steps of delignifying the cellulose fiber material prior to mixing the biocide with the fiber material. Lignin is then added to the biocide fiber substrate prior to mixing with the plastic material.
Another aspect of the present invention is a method of producing a fiber-plastic composition. This method comprises obtaining a fiber material, delignifying the fiber material to form a delignified fiber material, and drying the delignified fiber material. At least one chemical is then added to the delignified fiber material to chemically treat the fiber material. Lignin is then added to the delignified fiber material, and the fiber and lignin are mixed with a plastic material. One example of the chemical added to the delignified fiber material is at least one biocide.
Another aspect of the present invention is a method of producing a biocidic fiber material. According to this method, a cellulose fiber material is mixed with at least one biocide. The biocide replaces hydroxyl groups at the end of the cellulose molecule with chlorine.
A further aspect of the present invention is a product made according to any one of the methods defined above.
Yet another aspect of the present invention is a biocidic fiber-plastic composition comprising a fiber material, at least one biocide bound to the fiber material, and a plastic material bound to the fiber material.
The biocide used in the above methods and products preferably includes at least one biocide capable of replacing hydroxyl groups at the end of the cellulose molecule with chlorine. In one example, the biocide includes one or more of the following: Sodium Hypochlorite, N-chloro-p-toluenesulfonamide sodium salttrihydrate, and Vitamin E. The fiber material can be obtained from recycled agricultural waste. The plastic material can be obtained from recycled industrial waste.